On the hybrid motor vehicle driven by the driving forces of the internal combustion engine and the electric motor or the electric motor vehicle driven by the driving force of the electric motor, the power supply device is mounted and the power supply device serves to charge and discharge electric energy. Such a power supply device includes a cell assembly configured by a plurality of cells. In order to obtain a desired voltage, the plurality of cells are connected together in series. As the cell, a nickel hydrogen cell or a lithium ion cell is employed that is smaller and lighter, and higher in its supply voltage than the nickel hydrogen cell.
In the above-described power supply device, a positive electrode of one cell of the plurality of mutually adjacent cells is connected to a negative electrode of other cell by a connecting member to connect the plurality of cells in series. However, since a plurality of connecting members needs to be attached to the cell assembly, a problem arises that an assembly work is inconveniently complicated.
To solve the above-described problem, various power supply devices have been used (for instance, see patent literature 1). Such kind of power supply device includes a cell assembly having a plurality of cells, a plurality of connecting members that connect positive electrodes of one adjacent electrodes to negative electrodes of other cells of the cell assembly and a plate which is overlapped on the cell assembly and to which the plurality of connecting members are attached. On the outer peripheral surfaces of the positive electrodes and the negative electrodes, thread grooves are formed. In the plurality of connecting members and the plate, a plurality of holes are provided through which the positive electrodes and the negative electrodes are passed.
When the above-described power supply device is assembled, initially, the plurality of cells are overlapped and arranged in such a way that the positive electrodes and the negative electrodes of the mutually different cells are adjacent to each other. Subsequently, the plate to which the plurality of connecting members are attached is overlapped on the cell assembly, and the holes of the plate and the holes of the connecting members are respectively allowed to pass through the electrodes of the cells to attach the plate and the connecting members to the cell assembly. Then, nuts are screwed to the electrodes to fix the cell assembly to the plate and the connecting members.
[Patent literature 1] JP-A-2004-95381